I. Field of the Invention
The present invention relates to image reproduction and, more particularly, is directed towards a method and apparatus involving digital screen generation for reproducing an image.
II. Description of the Prior Art
The process of raster reproduction of continuous tone originals by a halftone representation is well known in the art. Generally, halftone processing utilizes line-by-line electrooptical scanning of the original in conjunction with optical screening techniques to produce halftone cells. A screen or mask having opaque rulings separating transmissive halftone cells are added optically to an image in order to form a resulting halftone image (U.S. Pat. No. 3,904,816). The optical half-tone screen adds or multiplies the image, cell-by-cell, by its transmittance function. The combined image is reproduced as a halftone image on a photographic film. The size and shape of the halftone cells forming the final image is dependent upon the mask used, differing optical effects being dependent upon the screen used. The use of electronic screening techniques is disclosed in U.S. Pat. Nos. 3,961,132; 4,080,634 and 4,149,194.